The universal serial bus (USB) standard has recently attracted attention as an interface standard for connections between personal computers and peripheral devices (generally speaking: electronic instruments). This USB standard has the advantage of enabling the use of connectors of the same standard to connect peripheral equipment such as a mouse, keyboard, and printer, which are connected by connectors of different standards in the prior art, and of making it possible to implement plug-and-play and hot-plug features.
In comparison with the IEEE 1394 standard which is also attracting notice as a standard for the same serial bus interface, this USB standard has a problem in that the transfer speed thereof is slower.
In this case, attention is being paid to the decision to use the USB 2.0 standard which can implement a data transfer speed of 480 Mbps (in HS mode), far faster than those of the previous USB 1.1 standard, while maintaining backward compatibility with USB 1.1. The USB 2.0 transceiver macrocell interface (UTMI), which defined interface specifications for the physical-layer and logical-layer circuitry under USB 2.0, has also been decided upon.